- Make sure the database 'modsec' is present on the system and it has the table 'modsec' in it.
- Do 'use modsec;repair table modsec' in MySQL prompt (via SSH)
- If everything is OK, run the script manually perl /etc/cron.hourly/modsecparse.pl

If all fails, remove an re-add the mod_security module through WHM (make sure you make a copy of your rules first)